The present invention relates to a support element for a heddle bar, particularly in a heddle frame, and a heddle frame having a support element.
The increasing speeds in modern weaving machines cause over-proportional increasing stresses on the heddle frames.
Accelerations of more than 30 g's occur already now and that clearly exceeds the stress limit of currently known designs.
There is a new approach necessary to find a solution and to respond to the increasing stresses foreseeable in the future. From patent literature and from the few described examples there are attempts disclosed for a solution, which were, however, without success for various reasons. Approaches can be seen in U.S. Pat. Nos. 4,484,604, 4,913,193, and EP 0 457 210 to replace the currently used materials of aluminum and steel with carbon-reinforced synthetic materials. Japanese patent document S60-47942, U.S. Pat. Nos. 4,790,357 and 4,913,194, as well as EP 0 288 652 disclose proposals on how different materials could be combined.
All these approaches have in common the attempt to retrofit the current traditional type of a support bar for heddle frames with a variety of materials. This has the result that many compromises have to be made relative to the employment of high-performance materials, as, for example, carbon-fiber reinforcement in the plastic profiled pieces.
It may be prudent to employ costly materials, such as carbon-fiber reinforced profiled pieces, only where the fibers may be arranged unidirectionally and where the effect is the best for geometrical reasons. The use of such reinforcements must, however, be limited to a minimum, particularly for cost reasons. Therefore, it is clearly sensible, as it is disclosed in U.S. Pat. No. 4,790,357, to manufacture part of the heddle frame of metal, e.g. the side pieces of the support bar.
However, all mentioned proposals follow the current idea in design, which includes the use of the heddle mounting rail as an essential supporting element. This is also reasonably sensible as long as the currently standard systems or shapes of the heddle support bar are kept the same. However, this type of design has the disadvantage that carbon-fiber reinforced profiled pieces can be used really effectively only at one of the outer sides. On the other side is the heddle mounting rail attached and it must be located at a considerably large distance away from the actual supporting profiled piece, according to present systems. Integration of the heddle mounting rail as a support element is sensible as long as the modulus of elasticity of the heddle mounting rail is considerably higher than the one of the remaining materials used for support.